/*
 * Copyright 2017 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrSimpleMeshDrawOpHelper_DEFINED
#define GrSimpleMeshDrawOpHelper_DEFINED

#include "include/gpu/GrRecordingContext.h"
#include "src/gpu/ganesh/GrMemoryPool.h"
#include "src/gpu/ganesh/GrOpFlushState.h"
#include "src/gpu/ganesh/GrPipeline.h"
#include "src/gpu/ganesh/GrRecordingContextPriv.h"
#include "src/gpu/ganesh/ops/GrMeshDrawOp.h"
#include "src/gpu/ganesh/ops/GrOp.h"
#include <new>

struct SkRect;

/* *
 * This class can be used to help implement simple mesh draw ops. It reduces the amount of
 * boilerplate code to type and also provides a mechanism for optionally allocating space for a
 * GrProcessorSet based on a GrPaint. It is intended to be used by ops that construct a single
 * GrPipeline for a uniform primitive color and a GrPaint.
 */
class GrSimpleMeshDrawOpHelper {
public:
    /* *
     * This can be used by a Op class to perform allocation and initialization such that a
     * GrProcessorSet (if required) is allocated as part of the the same allocation that as
     * the Op instance. It requires that Op implements a constructor of the form:
     * Op(ProcessorSet*, GrColor, OpArgs...).
     */
    template <typename Op, typename... OpArgs>
    static GrOp::Owner FactoryHelper(GrRecordingContext *, GrPaint &&, OpArgs &&...);

    // Here we allow callers to specify a subset of the GrPipeline::InputFlags upon creation.
    enum class InputFlags : uint8_t {
        kNone = 0,
        kSnapVerticesToPixelCenters = (uint8_t)GrPipeline::InputFlags::kSnapVerticesToPixelCenters,
        kConservativeRaster = (uint8_t)GrPipeline::InputFlags::kConservativeRaster,
    };
    GR_DECL_BITFIELD_CLASS_OPS_FRIENDS(InputFlags);

    GrSimpleMeshDrawOpHelper(GrProcessorSet *, GrAAType, InputFlags = InputFlags::kNone);
    ~GrSimpleMeshDrawOpHelper();

    GrSimpleMeshDrawOpHelper() = delete;
    GrSimpleMeshDrawOpHelper(const GrSimpleMeshDrawOpHelper &) = delete;
    GrSimpleMeshDrawOpHelper &operator = (const GrSimpleMeshDrawOpHelper &) = delete;

    GrDrawOp::FixedFunctionFlags fixedFunctionFlags() const;

    // ignoreAAType should be set to true if the op already knows the AA settings are acceptible
    bool isCompatible(const GrSimpleMeshDrawOpHelper &that, const GrCaps &, const SkRect &thisBounds,
        const SkRect &thatBounds, bool ignoreAAType = false) const;

    /* *
     * Finalizes the processor set and determines whether the destination must be provided
     * to the fragment shader as a texture for blending.
     *
     * @param geometryCoverage Describes the coverage output of the op's geometry processor
     * @param geometryColor An in/out param. As input this informs processor analysis about the
     * color the op expects to output from its geometry processor. As output
     * this may be set to a known color in which case the op must output this
     * color from its geometry processor instead.
     */
    GrProcessorSet::Analysis finalizeProcessors(const GrCaps &caps, const GrAppliedClip *clip, GrClampType clampType,
        GrProcessorAnalysisCoverage geometryCoverage, GrProcessorAnalysisColor *geometryColor)
    {
        return this->finalizeProcessors(caps, clip, &GrUserStencilSettings::kUnused, clampType, geometryCoverage,
            geometryColor);
    }

    /* *
     * Version of above that can be used by ops that have a constant color geometry processor
     * output. The op passes this color as 'geometryColor' and after return if 'geometryColor' has
     * changed the op must override its geometry processor color output with the new color.
     */
    GrProcessorSet::Analysis finalizeProcessors(const GrCaps &, const GrAppliedClip *, GrClampType,
        GrProcessorAnalysisCoverage geometryCoverage, SkPMColor4f *geometryColor, bool *wideColor);

    bool isTrivial() const
    {
        return fProcessors == nullptr;
    }

    bool usesLocalCoords() const
    {
        SkASSERT(fDidAnalysis);
        return fUsesLocalCoords;
    }

    bool compatibleWithCoverageAsAlpha() const
    {
        return fCompatibleWithCoverageAsAlpha;
    }

    void visitProxies(const GrVisitProxyFunc &func) const
    {
        if (fProcessors) {
            fProcessors->visitProxies(func);
        }
    }

#if defined(GR_TEST_UTILS)
    SkString dumpInfo() const;
#endif
    GrAAType aaType() const
    {
        return static_cast<GrAAType>(fAAType);
    }

    void setAAType(GrAAType aaType)
    {
        fAAType = static_cast<unsigned>(aaType);
    }

    static const GrPipeline *CreatePipeline(const GrCaps *, SkArenaAlloc *, skgpu::Swizzle writeViewSwizzle,
        GrAppliedClip &&, const GrDstProxyView &, GrProcessorSet &&, GrPipeline::InputFlags pipelineFlags);

    static const GrPipeline *CreatePipeline(GrOpFlushState *, GrProcessorSet &&, GrPipeline::InputFlags pipelineFlags);

    const GrPipeline *createPipeline(GrOpFlushState *flushState);

    const GrPipeline *createPipeline(const GrCaps *, SkArenaAlloc *, skgpu::Swizzle writeViewSwizzle, GrAppliedClip &&,
        const GrDstProxyView &);

    static GrProgramInfo *CreateProgramInfo(const GrCaps *, SkArenaAlloc *, const GrPipeline *,
        const GrSurfaceProxyView &writeView, bool usesMSAASurface, GrGeometryProcessor *, GrPrimitiveType,
        GrXferBarrierFlags renderPassXferBarriers, GrLoadOp colorLoadOp,
        const GrUserStencilSettings * = &GrUserStencilSettings::kUnused);

    // Create a programInfo with the following properties:
    //     its primitive processor uses no textures
    //     it has no dynamic state besides the scissor clip
    static GrProgramInfo *CreateProgramInfo(const GrCaps *, SkArenaAlloc *, const GrSurfaceProxyView &writeView,
        bool usesMSAASurface, GrAppliedClip &&, const GrDstProxyView &, GrGeometryProcessor *, GrProcessorSet &&,
        GrPrimitiveType, GrXferBarrierFlags renderPassXferBarriers, GrLoadOp colorLoadOp,
        GrPipeline::InputFlags pipelineFlags = GrPipeline::InputFlags::kNone,
        const GrUserStencilSettings * = &GrUserStencilSettings::kUnused);

    GrProgramInfo *createProgramInfo(const GrCaps *, SkArenaAlloc *, const GrSurfaceProxyView &writeView,
        bool usesMSAASurface, GrAppliedClip &&, const GrDstProxyView &, GrGeometryProcessor *, GrPrimitiveType,
        GrXferBarrierFlags renderPassXferBarriers, GrLoadOp colorLoadOp);

    GrProcessorSet detachProcessorSet()
    {
        return fProcessors ? std::move(*fProcessors) : GrProcessorSet::MakeEmptySet();
    }

    GrPipeline::InputFlags pipelineFlags() const
    {
        return fPipelineFlags;
    }

protected:
    GrProcessorSet::Analysis finalizeProcessors(const GrCaps &caps, const GrAppliedClip *,
        const GrUserStencilSettings *, GrClampType, GrProcessorAnalysisCoverage geometryCoverage,
        GrProcessorAnalysisColor *geometryColor);

    GrProcessorSet *fProcessors;
    GrPipeline::InputFlags fPipelineFlags;
    unsigned fAAType : 2;
    unsigned fUsesLocalCoords : 1;
    unsigned fCompatibleWithCoverageAsAlpha : 1;
    SkDEBUGCODE(unsigned fMadePipeline : 1;) SkDEBUGCODE(unsigned fDidAnalysis : 1;)
};

template <typename Op, typename... Args>
GrOp::Owner GrOp::MakeWithProcessorSet(GrRecordingContext *context, const SkPMColor4f &color, GrPaint &&paint,
    Args &&... args)
{
    char *bytes = (char *)::operator new(sizeof(Op) + sizeof(GrProcessorSet));
    char *setMem = bytes + sizeof(Op);
    GrProcessorSet *processorSet = new (setMem)GrProcessorSet{ std::move(paint) };
    return Owner{ new (bytes)Op(processorSet, color, std::forward<Args>(args)...) };
}

template <typename Op, typename... OpArgs>
GrOp::Owner GrSimpleMeshDrawOpHelper::FactoryHelper(GrRecordingContext *context, GrPaint &&paint, OpArgs &&... opArgs)
{
    auto color = paint.getColor4f();
    if (paint.isTrivial()) {
        return GrOp::Make<Op>(context, nullptr, color, std::forward<OpArgs>(opArgs)...);
    } else {
        return GrOp::MakeWithProcessorSet<Op>(context, color, std::move(paint), std::forward<OpArgs>(opArgs)...);
    }
}

GR_MAKE_BITFIELD_CLASS_OPS(GrSimpleMeshDrawOpHelper::InputFlags)

#endif
